U.S. Vice President Dick Cheney meets the ruler of Oman Wednesday to discuss concerns about Iran's growing influence in the Middle East.

Oman is the second stop on Cheney's nine-day tour of the region. He began with a previously unannounced two-day visit to Iraq.

U.S. officials say Iran will be high on the agenda of Cheney's talks with Oman's Sultan, Sheikh Qaboos bin Said. They say Omanis are concerned about escalating tensions between Iran and the world community over Iran's nuclear program and its activities in Iraq.

U.S. officials say Cheney will thank Oman for its cooperation in the war against terrorism. Oman is a U.S. ally that allows U.S. forces to use its air bases for refueling and logistics. But, the Gulf state also maintains good relations with Iran, which lies across the Strait of Hormuz.

Cheney and Sultan Qaboos have a personal friendship that goes back to the early 1990s, when Cheney served as U.S. defense secretary under President George H.W. Bush. Ahead of Wednesday's talks, Sultan Qaboos lent his royal yacht to Cheney, his wife Lynne and daughter Liz for a fishing trip in the waters off Oman's capital, Muscat.